PCDD/F

These results show the fate of aromatic bromine compounds during municipal waste incineration bromine is exchanged by chlorine on the surface of fly ash at the electrostatic precipitator at 250-3(X)°C. But the toxic potential at brominated dibenzodioxins and furans is not reduced by these transformations. The increase of PCDD/F concentration in MWI by adding bromine compounds has been pointed out by Lahl and coworkers (ref. 26). 

Energy recovery from packaging waste is discussed, with particular reference to the co-combustion of mixed plastics with other conventional fuels such as wood, coal and peat. Experimental work is described in which a project was established to evaluate the possibility of energy recovery from a circulating fluidised bed boiler using packaging from different sources as fuel. The role of sulphur in the formation of PCDD/F in the combustion process was also studied. 

Based on the values of Cpcdd/fs [46], Ccipahs [38], and CBfrs in e-waste, the annual mass emissions of selected PCDD/F and C1PAH congeners and BFRs from e-waste are estimated (Table 3). The lowest annual mass emission of PBDEs is about 82,207 tons/year, with 70,607 tons/year from importation and 11,600 tons/ year from domestic generation (Table 3). Nona- and deca-BDEs are the most important congeners as they are the major constituents of BRFs in electronic equipment [77]. In addition, the annual mass emissions of PBBs, TBBPA, and PBPs are also estimated with the same procedure (Table 3). Obviously, importation is responsible for the majority of annual mass emissions of e-waste-derived organic pollutants in China (Table 3). 

Li HR, Yu LP, Sheng GY, Fu JM, Peng PA (2007) Severe PCDD/F and PBDD/F pollution in air around an electronic waste dismantling area in China. Environ Sci Technol 41 (16) 5641-5646. doi 10.1021/es0702925... 

Domingo JL, Schuhmacher M, Agramunt MC, Llobet JM, Rivera J, Muller L (2002) PCDD/F levels in the neighbourhood of a municipal solid waste incinerator after introduction of technical improvements in the facility. Environ Int 28(l-2) 19-27. doi 10.1016/S0160-4120(01)00129-5... 

PCDD/F re-emission flux from soil, which slows down the tendency for a decrease in PCDD/F content in the atmosphere. 

The distribution of the annual emissions of PCDD/F in the atmosphere of the F.MFP region in 2001 as compared with their distribution between different environmental compartments by the end of the calculated period is presented in Figure 7. Only 1 % of the annual PCDD/F emissions remains in the atmosphere about 56% are deposited to other media. However, the distribution between media after a long time period is not directly determined by PCDD/Fs depositions in 2001. To a great extent it results from their long-term accumulation in the environment (1970-2001). For example, the annual contribution of PCDD/Fs total emissions to soil is about 47%. However, after a long time period the most part of the total PCDD/Fs content in the environment (about 95%) accumulated in soil due to relatively low degradation rates for this medium. Thus, soil is the main medium-accumulator of PCDD/Fs. 

Figure 7. Distribution of annual emissions of the mixture of toxic PCDD/F congeners in the atmosphere (a) and environmental content between different environmental compartments (b) in 2001 (Shatalov et al., 2004).

Re-emission of toxic congeners from soil to the atmosphere can affect the levels of PCDD/F air pollution. 

To identify the areas and regions which were the most polluted by the considered POPs, the preliminary model results on the spatial distribution of their concentrations in different environmental media of the EMEP region were obtained. As an example, the spatial distributions of PCDD/F concentrations in soil, vegetation and seawater with a spatial resolution of 50 x 50 are presented in Figure 8. 

Thermal reactions leading to the PCDD/F emissions are connected with technological and domestic combustion. PCDD/Fs were found in the emissions of the various combustion processes independently from the fuel municipal and hazardous waste incinerators, power plants with fossil fuels, automobile exhaust, private heating and fire places, wood and forest fires,... 

Gihr and co-workers 8 estimated PCDD/F sources to sewage sludge and made two important observations. Firstly, known sources of PCDD/Fs (like polychlorophenols - PCP) cannot explain the total burden in sewage sludge and secondly, that while PCP-associated PCDD/Fs can account for the... 

PRELIMIARY MEASUREMENTS OF PCDD/F LEVELS IN POLISH SLUDGE... 

Table 1. PCDD/F concentrations (ng/kg dry matter) in the sludge samples.

TEQ calculations were made based on both - the WHO-TEFs and I-TEFs for seventeen 2,3,7,8-substituted PCDDs and PCDFs. Dioxin like PCBs were not measured. Total WHO-TEQ PCDD/F values for the analyzed samples range from 53.50 to 65.26 ng/kg dry mass. Calculations, based on I-TEFs were also made, to allow comparison with the literature data. The variation in the TEQ concentration may be attributed to varying loads during the sample collection period. Obtained results are higher, than medium... 

Table 2. PCDD/F range in sewage sludge from different European countries.

Because PCDD/Fs became to be recognized as the most hazardous for the environment and human beings, very restricted emission limits were introduced in the most countries. But only a few countries limits are also pursuit for PCDD/F levels in sewage sludge, however sludge is one of the ultimate sinks for persistent chemicals. 

Particular attention has been focused on the application of sewage sludge to agricultural land in the context of PCDD/F additions, given the propensity for the 2,3,7,8-substituted compounds to bioaccumulate into livestock. 

European Dioxin Inventory, 1999, Report for European Commission, DG XI. Hutzinger O., Fiedler, H., Sources and Emissions of PCDD/F, Chemosphere 18,1989,23-32. 

Oberg, L.G., Rappe, C., Biochemical formation of PCDD/F from chlorophenols, Chemosphere 25, 1992, 49-52. 

Dudzinska, M.R., Czerwinski, J., PCDD/F levels in sewage sludge from MWTP in South-Eastern Poland, Organohalogen Compounds, 57,2002,305-308. 

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

All accidents concerned with PCDD/F are related to the production of chlorophenols. The most famous accident happened in Seveso close to Milan, Italy, on July 10, 1976. ICMESA Corp. manufactured 2,4,5-trichlorophenol for production of phenoxy-herbizides by alkaline hydrolysis of 1,2,4,5-tetrachlorobenzene (see Figure 8.1). This... 

Dioxins are mainly by-products of industrial processes, but can also result from natural processes, such as volcanic eruptions and forest fires. Besides the anthropogenic (man-made) sources of PCDD/F discussed earher, biogenic and geogenic sources for dioxins also have been discovered recently. In natural clays of the kaohnite-type found in German mines in Westerwald, considerable levels of PCDD / F have been detected the same findings were obtained in special ball clays in the Mississippi area of the United States. The pattern (isomeric ratios) of this natural type of dioxins is different from the pattern obtained from incineration plants. 

The PCDD/F class consists of 210 compounds, 75 isomers of PCDD, and 135 isomers of PCDF. The number of regioisomers are the following according to the number of chlorine atoms in either skeleton (see Table 8.2). 

All PCDD/F isomers are solids with high melting points, but low vapor pressure and low solubihty in water. The high octanol-water coefficients are an indication of the observed bioaccumulative behavior in plants and animals for these compounds. Detailed environmentally important physicochemical properties can be found in the literature. All higher chlorinated compounds are very persistent in the environment with half-lives of 5-10 years photolysis with sunlight is the only degradation process in the environment. 

Figure 8.2 Scheme for the cleanup method of PCDD/F in sediments. 

The dioxin toxic equivalency factor (TEF) approach is currently used worldwide for assessing and managing the risks posed by exposure to mixtures of certain dioxin-like compounds (DLCs). World Health Organization-TEF (WHO-TEE) values have been established for humans and mammals, birds, and (For new, refined values, see Ref. 12g.) It should be mentioned that 16 PCBs, the coplanar isomers with nonortho, monoortho, and diortho substitution by chlorine (overall, there are 209 isomers for this class of compounds) show dioxin-like toxic behavior. I-TE values are smaller, in the range of 0.0001-0.1. The most toxic isomers is 3,3, 4,4, 5-pentachlorodiphenyl with I-TE of 0.1. Polybrominated dibenzodioxins and furans with the 2,3,7,8 pattern also show dioxin-like toxicity, but their I-TE values are lower compared to PCDD/F. 

Primary and Secondary Measures for Minimization of PCDD/F in Incineration Plants... 

PCDD/F are emitted by the flue gas of the incineration plants. Primary measures have become very important in the production and technology of chemistry as the... 

TABLE 8.3 Toxic Equivalency Factors (TEFs) for Toxic PCDD/F Isomers According to NATO/CCMS (1988) and WHO I-TE... 

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